Signal will build the vessel at its Orange, Texas, shipyard, raising employment there from 100 to 500 during the 14-month project, Signal CEO Dick Marler said. Kirby has an option for an additional unit that would take 12 months to build.

Signal, which is owned partly by the Retirement Systems of Alabama, operates repair yards for ships and oil rig equipment in Mobile, Pascagoula and Texas.

"This is a big breakthrough for us," Marler said of the Kirby contract. "This puts us squarely back into shipbuilding."

The barge will be 480 feet long and will be able to hold 20,000 tons. The 6,000-horsepower tug will be 125 feet long.

Kirby will use the vessel for domestic shipping of dry-bulk commodities such as coal, grain or gravel.

Signal employs 700 workers in Pascagoula and about 250 in Mobile, Marler said.